There are many types of radiation measurement devices that are commercially available. These units include very expensive and bulky devices having high energy consumption. There are also sophisticated types of units that may require a detailed knowledge of science and physics in order to interpret or otherwise gather information from.
One family of detectors is commonly referred to as scintillation detectors. These instruments include a photodetector viewing a radioluminescent (phosphor) material. Particles indicative of harmful radiation strike and excite the phosphor. The resulting light signal is then picked up by the photodetector. A traditional scintillation detector is efficient when a large surface area of photocell is able to be covered with phosphor material. It is impractical to use these existing radiation detectors as convenient personal detection devices, because if the detector is made small enough for personal use, then there is not enough sensitivity to detect low, but still potentially harmful, levels of radiation.